Generation and measurement of extreme magnetic fields

Next-generation laser facilities may reach extreme intensities (>10²³ W/cm²), allowing for the effects of quantum electrodynamic (QED) processes on plasmas to be studied. In the interaction of such high intensity pulses with solid targets it is expected that ~0.1 MT magnetic fields may be generated, potentially allowing for the experimental study of extreme astrophysical phenomena. Currently, there is no theoretical description for how such extreme laser intensities affect the magnetic field generation and strength. For example, the magnetization that ultra-intense laser interactions will achieve may be limited by QED processes, i.e. radiation reaction, and therefore cannot be accurately predicted. Using the QED module in the OSIRIS particle-in-cell code, we perform several 2D and quasi-3D simulations to study magnetic field generation at these extreme laser intensities. In the expected range of magnetic field strengths standard proton deflectometry techniques cannot be used due to the extremely large deflections of the protons. We propose an electron radiography method to measure the properties of these magnetic fields.